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SENSE reconstruction for multiband EPI including slice‐dependent N/2 ghost correction
Author(s) -
Hennel Franciszek,
Buehrer Martin,
von Deuster Constantin,
Seuven Aline,
Pruessmann Klaas P.
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25915
Subject(s) - sense (electronics) , computer science , algorithm , phase (matter) , encoding (memory) , sensitivity (control systems) , image (mathematics) , echo planar imaging , wafer , artificial intelligence , physics , chemistry , magnetic resonance imaging , optoelectronics , quantum mechanics , electronic engineering , engineering , medicine , radiology
Purpose Sensitivity encoding (SENSE) reconstruction of multiband echo planar imaging (EPI) may cause artifacts when simultaneously excited slices require different phase correction to remove the EPI‐specific ghost shifted by half of the matrix size (N). We propose a simplified solution of this problem that combines SENSE unfolding with the EPI phase correction in the image domain. Theory and Methods Slice‐dependent phase correction was included in equations linking folded slice images reconstructed separately from even and odd echoes of all receivers with the true images of each slice. Compared with the previously proposed combination of ghost suppression with SENSE based on a direct image fit to echo data, our method reduces the problem complexity by N 2 /4. It was applied to reconstruct images of phantoms and human brain. Results The proposed method tolerates high differences of phase correction between slices, which may result, e.g., from anisotropic gradient delay. It suppresses artifacts better than standard SENSE even when the latter is repeated with the ghost correction targeting each of the slices and works significantly faster than the direct fit version of ghost‐correcting SENSE. Conclusion With the proposed modification SENSE allows a rapid separation of slices simultaneously acquired with EPI even when the phase correction needed for each slice is different. Magn Reson Med 76:873–879, 2016. © 2015 Wiley Periodicals, Inc.